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Baron attends Nonlinear Optics Conference

August 1, 2015

By:

Alex Baron

From July 26th to 31st, I had the chance of attending the Nonlinear Optics conference (NLO), organized by the Optical Society of America in Hawaii. This year, it was held at the Kaua’i Marriott Resort on Kalapaki Beach. It is an international gathering of top scientists that discuss all aspects of nonlinear optics, including new phenomena, novel devices, advanced materials and applications in the field. Thanks to its excellent climate and beautiful landscapes, Hawaii is a very attractive destination for a conference. NLO is held every two years.

This conference was a great opportunity for me to get up to speed with the current trends and investigations in Nonlinear Optics. In recent years, the field has come to overlap a lot with plasmonics and metamaterials, giving rise to the fields of nonlinear plasmonics and nonlinear metamaterials.

I contributed a talk to the conference in the Nonlinear Plasmonics session entitled Nonlinear Metal/Dielectric Plasmonic Interfaces. With this contribution, I presented work, which was a collaboration involving David Smith’s Meta Group as well as Dan Gauthier’s and Maiken Mikkelsen’s groups. I presented our recent theoretical and experimental investigations into the optical nonlinearity of metal/dielectric interfaces. Our work provides insight into the mechanisms of self-action of surface plasmons for this type of geometry as well as means to measure the third-order nonlinear susceptibility of metals. As a matter of fact, I got the audience very interested by showing that we were able to precisely measure the bulk nonlinear susceptibility of gold using surface plasmon polaritons. Unfortunately, the talk following mine was cancelled, but it turned out to be an excellent opportunity for questions and discussions concerning our work to extend for about fifteen minutes. Robert W. Boyd (U. Ottawa, Ca), Mark Stockman (Georgia Tech), Ortwin Hess (Imperial College, UK) and Martti Kauranen (U. of Tampere, Finland) all approached me to discuss the large values of the third-order susceptibility that we measured, which far exceed previously measured values using alternative techniques, such as z-scan. Bob Boyd suggested that the differences might come from the fact that surface plasmons are “tricky” perhaps, in the sense that they probe nonlinearities differently from waves focused into a thin metal film.

This year, the organizers had a very clever idea to encourage people to ask questions: they organized a Best Question award. I won the $250 prize for best question for my questions to Peter Rakich (Yale University) in the Stimulated Scattering and Optomechanics session. He presented very nice work on the control of coherent information via traveling-wave photon-phonon interactions, a lot of which is done by leveraging Stimulated Brillouin Scattering (SBS) in silicon. He also showed impressive electrostriction maps in silicon, which reminded me of coordinate transforms.

My question to him was: “When I see the electrostriction maps in both yours and Ben Eggleton's presentations, I see a coordinate transformation. Do you think we could have an SBS approach to transformation optics? For instance, could we imagine building, at least in theory, an SBS activated cloak?”

His answer was: “I have absolutely no idea how to answer this, but it sounds really nice, we should definitely talk!”

The keynote speaker this year was W. E. Moerner, who gave a presentation entitled “Light Paves the Way to Single-Molecule Detection and Photocontrol: Foundations of Super-Resolution Microscopy.” Another noteworthy talk was given by Bob Boyd on the optical Kerr effect in ITO. His presentation was entitled “Unity-order Intensity-Dependent Change in Refractive Index in Indium-Tin Oxide at its Epsilon-Near-Zero Wavelength”. He showed experimentally that near the wavelength at which the dielectric constant of ITO becomes null, the nonlinear index n2 is very high and large (near-unity) changes in the refractive index can be achieved.

This conference was great and I encourage people involved in nonlinear optics at Duke to attend it in two years!